Machines such as, for example, wheeled loaders, tracked loaders, track type tractors, and other types of heavy machinery, may be used for a variety of tasks. These machines may include a prime mover, which may include, for example, an engine, such as a diesel engine, gasoline engine, or natural gas engine that provides the power required to perform tasks using one or more torque consuming devices.
When the torque consuming devices require an increase in torque, a demand for increased power may be placed on the engine. Similarly, when the torque consuming devices require less torque, a demand for decreased power may be placed on the engine. Such changes in demand are traditionally countered by increasing or decreasing fuel delivery to the engine. However, due to response delays of various engine systems and the relative immediacy of changes in demand, engine speed may either droop under or shoot over a desired engine speed. Another difficulty associated with torque consuming devices is that operation of these devices may produce loads on the engine that may be severe enough to cause stalling or lugging of the engine, collectively referred to as excessive engine speed droop. Lugging or stalling the engine may decrease the productivity and efficiency of the engine. The torque consuming devices may also become unstable because the time required for the engine to respond to the changes in demand can be greater than the demand period.
One attempt to control machine operation is described in U.S. Pat. No. 7,146,263 B2 to Guven et al. (“Guven”). Guven discloses a method for predictive load management. In Guven, a control system is operable to receive at least one input indicative of a load on a transmission and to identify a desired load of the transmission based on the at least one input. The control system is also operable to receive at least one input indicative of current power output of a power source. The control system limits the desired transmission load applied to the driven member of the transmission based on the current power output of the power source to thereby prevent the power source from operating outside of the desired operating range. However, the method in Guven may be inefficient.
The disclosed system and method is directed at overcoming one or more of the problems set forth above.